1. Field of the Invention
The present invention generally relates to a semiconductor device and a method for forming the same, and more particularly, the present invention relates to the semiconductor device and the method for forming the same, having a borophosphosilicate glass film as an interlayer insulator.
This application is a counterpart of Japanese application Serial Number 155220/1998, filed May 20, 1998, the subject matter of which is incorporated herein by reference.
2. Description of the Related Art
In general, a multi-level interconnection is used effectively to provide the advantage of high integration. In the multi-level interconnection, an interlayer insulator is formed between interconnections. A borophosphosilicate glass film as the interlayer insulator is used for planarization in VLSI circuit.
The borophosphosilicate glass film covers an active region of a semiconductor device such as a MOS transistor. After then, the borophosphosilicate glass film is reflowed using thermal treatment. As a result, the interlayer insulator having a smooth surface is formed.
However, phosphorus in the borophosphosilicate glass film is diffused to the active region of the semiconductor device during reflow. It is desirable to avoid the outdiffusion of the phosphorus to the active region of the semiconductor device.